Even if development is not public, the source code is licensed as open-source and it can be forked, which is the whole freaking point. Amazon could fork it. Nokia could fork it. One can argue that CyanogenMod is a fork as well.

What makes little sense is to start again, mostly from scratch (or from MeeGo or its successor, which is basically from scratch). This project is a failure before they started working on it.

And good luck finding a hardware manufacturer willing to produce devices with your forked version thanks to Google's draconian agreements with manufacturers.

Given that there are in fact phones on the market that do not include Google's Play or apps, such assertions need references. So what "draconian agreements" are you talking about?

That would be these agreements: http://bgr.com/2014/02/13/google-play-terms-of-service/

“the agreement places a company-wide ban on Android forks, saying OEMs are forbidden from taking ‘any actions that may cause or result in the fragmentation of Android’ and specifically disallows distributing or encouraging a third-party to distribute ‘a software development kit derived from Android.'”

Not so very open after all?

The people who have forked android have great difficulty finding OEMs to manufacture thrir devices as the list of those who don't have agreements with Google is rather short.

No one ever said that Google's services were open. The operating system itself is open. instead of starting from 0, Yandex could just modify Android and have their own market, maps... People been bitching about fragmentation in Android for years, when google changed their agreement to counter it, people are now bitching about the agreement.

The problem is that even if they create their own marketplace etc. any manufacturers who have an agreement with Google will be unable to manufacture any devices running the forked version. The restriction is company wide for the OEM.